Blue-throated Dwarf-Iguana (Enyalioides microlepis)

Reptiles of Ecuador | Sauria | Hoplocercidae | Enyalioides microlepis

English common names: Blue-throated Dwarf-Iguana, Small-scaled Woodlizard.

Spanish common names: Iguana enana gargantiazul, lagartija de palo microescamada.

Recognition: ♂♂ 31.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=12.7 cm. ♀♀ 26.4 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=11.6 cm..¹ Enyalioides microlepis differs from other medium-sized spiny lizards in the Ecuadorian Amazon by its granular dorsal scales, strongly projected spiny vertebral crest, skull roof (casque head flattened at the top), and unique coloration. The dorsum is yellowish-brown with jaguar-like brown spots, a dark subocular mark, and a blackish throat patch (blueish in males; Fig. 1).¹ The species further differs from the other dwarf iguanas in Amazonian Ecuador by having incomplete dorsolateral crests and lacking projecting, conical scales on top of dorsum.¹ This species is often confused with E. cofanorum. In adult males of the latter species, the projecting dorsal scales are present and the dorsolateral crests are complete and conspicuous.^1–3 Males of E. microlepis are larger than females and have a more contrasting coloration (Fig. 1).^1–3

Figure showing variation among individuals of Enyalioides microlepis

Figure 1: Individuals of Enyalioides microlepis from Gareno, Napo province, Ecuador.

Natural history: Enyalioides microlepis is an extremely rare lizard that is difficult to observe during the daytime due to its cryptic camouflage. This species occurs in pristine lowland rainforests, which may be terra-firme or seasonally flooded by white-water rivers.^1,4 Blue-throated Woodlizards are active during the daytime on shaded areas of the forest floor, staying immobile for prolonged periods of time on the leaf-litter or on logs.^1,4 At night, they roost on stems and twigs 0.4–1.0 m above the ground.^1,4 They have also been found hidden under logs.¹ Their preferred predator avoidance strategy is staying still and blending against the leaf-litter or running into cover.⁵

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..⁵ Enyalioides microlepis is listed in this category primarily on the basis of the species’ wide distribution, presumed stable populations, and presence in protected areas. Although, E. microlepis is considered rare, this is probably due to the difficulty of detecting individuals in the wild rather than to actual low population densities.

Distribution: Enyalioides microlepis is native to the western Amazon basin in Colombia, Ecuador (Fig. 2), and Perú.

Figure 2: Distribution of Enyalioides microlepis in Ecuador. The star corresponds to the type locality: Sarayacu, Pastaza province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Enyalioides, which comes from the Latin words Enyalius (a genus of neotropical lizards) and the suffix oides (=similar to), refers to the similarity between lizards of the two genera. The specific epithet microlepis comes from the Greek words mikros (=small) and lepis (=scale),⁶ and refers to the small scales on the dorsal aspect of the head and body.

See it in the wild: Blue-throated Dwarf-Iguanas are usually found in closed-canopy situations rather than in open or semi-open areas. These cryptic reptiles are easier to detect by sampling well-preserved forest trails at night with the aid of a flashlight. In this way, roosting individuals may be detected at a rate of 1–3 individuals per year. The localities having the greatest number of recent observations of this species are Gareno and Villano, Pastaza province.

Authors: Alejandro Arteaga^aAffiliation: Khamai Foundation, Quito, Ecuador. and Gabriela Aguiar^bIndependent researcher, Quito, Ecuador.

Photographer: Alejandro Arteaga^aAffiliation: Khamai Foundation, Quito, Ecuador. and Sebastián Di Doménico^cAffiliation: Keeping Nature, Bogotá, Colombia.

How to cite? Arteaga A, Aguiar G (2023) Blue-throated Dwarf-Iguana (Enyalioides microlepis). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/RPCC3337

Literature cited:

Torres-Carvajal O, Etheridge R, de Queiroz K (2011) A systematic revision of Neotropical lizards in the clade Hoplocercinae (Squamata: Iguania). Zootaxa 2752: 1–44. DOI: 10.11646/zootaxa.2752.1.1
Duellman WE (1978) The biology of an equatorial herpetofauna in Amazonian Ecuador. Publications of the Museum of Natural History, University of Kansas 65: 1–352.
Duellman WE (1973) Descriptions of new lizards from the upper Amazon basin. Herpetologica 29: 228–231.
Field notes, Reptiles of Ecuador book.
Caicedo J, Calderón M, Cisneros-Heredia DF, Ines Hladki A, Ramírez Pinilla M, Renjifo J, Urbina N, Perez P, Gagliardi G (2016) Enyalioides microlepis. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2016-1.RLTS.T44578920A44578931.en
Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.

Appendix 1: Locality data used to create the distribution map of Enyalioides microlepis in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

Country	Province	Locality	Source
Colombia	Amazonas	Puerto Nariño	Torres-Carvajal et al. 2011
Ecuador	Loreto	Pebas	Dixon & Soini 1986
Ecuador	Morona Santiago	Río Llushino	Torres-Carvajal et al. 2011
Ecuador	Morona Santiago	Río Santiago	Torres-Carvajal et al. 2011
Ecuador	Napo	Gareno	This work; Fig. 1
Ecuador	Pastaza	Andoas	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Arajuno	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Balsaura	Ortega-Andrade 2010
Ecuador	Pastaza	Campo Villano	Torres-Carvajal et al. 2023
Ecuador	Pastaza	Canelos	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Capahuari river, mouth of	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Chichirota	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Conambo	Ortega-Andrade 2010
Ecuador	Pastaza	Juyuintza	Ortega-Andrade 2010
Ecuador	Pastaza	Kurintza	Ortega-Andrade 2010
Ecuador	Pastaza	Lorocachi	Torres-Carvajal et al. 2023
Ecuador	Pastaza	Montalvo	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Moretecocha	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Paparawua	Torres-Carvajal et al. 2019
Ecuador	Pastaza	Pindoyacu	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Puerto Santana	iNaturalist; photo examined
Ecuador	Pastaza	Río Curaray	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Río Tigre	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Río Villano	Torres-Carvajal et al. 2011
Ecuador	Pastaza	Sarayacu*	O’Shaughnessy 1881
Ecuador	Pastaza	Tarangaro	Torres-Carvajal et al. 2019
Ecuador	Pastaza	Territorio Shiwiar	Ortega-Andrade et al. 2010
Ecuador	Pastaza	Villano	Torres-Carvajal et al. 2011
Perú	Amazonas	Aintami	Torres-Carvajal et al. 2011
Perú	Amazonas	Huampami	Torres-Carvajal et al. 2011
Perú	Amazonas	Kusu	Torres-Carvajal et al. 2011
Perú	Amazonas	Pais	Torres-Carvajal et al. 2011
Perú	Amazonas	Quebrada Shinganatza	Almendáriz et al. 2014
Perú	Amazonas	San Antonio, Río Cenepa	Torres-Carvajal et al. 2011
Perú	Amazonas	Sua, on the Río Cenepa	Torres-Carvajal et al. 2011
Perú	Loreto	Andoas	Venegas et al. 2011
Perú	Loreto	Barranca	Torres-Carvajal et al. 2011
Perú	Loreto	Capahuari norte	Venegas et al. 2011
Perú	Loreto	Mouth of Río Santiago	Torres-Carvajal et al. 2011
Perú	Loreto	Pozo Runtusapa	Venegas et al. 2011
Perú	Loreto	Puerto Soledad, 12 km E of	iNaturalist; photo examined
Perú	Loreto	San Jacinto	Torres-Carvajal et al. 2011
Perú	Loreto	Tutapisco	iNaturalist; photo examined